Pouch with spout

ABSTRACT

Provided is a spouted pouch, said pouch being suitable for achieving a high gas-barrier property. This pouch X is provided with a pouch main body  10  and a spout  20 . The pouch main body  10  is configured from a film having a sealant layer on an inner surface thereof. The spout  20  is an integrally molded resin body and contains each of an olefin-based resin and an ethylene-vinyl alcohol copolymer and is attached to the pouch main body by thermal welding with the sealant layer. The sealant layer is configured from an olefin-based resin film having a heat seal strength determined by the following peel test of 10 N/15 mm or less. The peel test: two olefin-based films each lined with a fracture prevention film are partially thermal-welded by an action of a compression pressure of 0.2 MPa for 1 second at 105° C., and thereafter the thermally welded section is subjected to a peel test under the condition of a tension rate of 300 mm/min at 23±2° C.

TECHNICAL FIELD

The present invention relates to a pouch with a spout.

BACKGROUND ART

Pouches have conventionally been utilized as commodity containers for soft drinks, jelly foods, soups, etc. A spouted pouch is known as one kind of pouches, the spouted pouch having a mouth called spout which is attached to a pouch main body. When opened, the spout is capable of serving as an outlet for pouring out the content. Such spouted pouches are described, for example, in Patent Literatures 1 to 3 listed below.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Laid-Open No. 2006-1623

Patent Literature 2: Japanese Patent Laid-Open No. 2012-111801

Patent Literature 3: Japanese Patent Laid-Open No. 2015-58967

SUMMARY OF INVENTION Technical Problem

The pouch main body of the spouted pouch is composed of a predetermined number of film materials which are joined together into the form of a bag by thermal welding. Each of the film materials may be a laminated film including: a sealant layer disposed on the surface of the film to achieve good thermal welding between the film materials; and a barrier layer having good gas barrier property. From the viewpoint of the sealability of manufactured pouches and the manufacturing cost, olefin resins such as polyethylene are widely used as the material for forming the sealant layer.

The spout of the spouted pouch is attached to the pouch main body by thermal welding to the sealant layer of the film material of the pouch main body. From the viewpoint of the thermal weldability to the sealant layer and the manufacturing cost, an integrally molded resin body made of an olefin resin is widely used for a spout, similarly to the sealant layer. However, olefin resins have considerably poor gas barrier property. Thus, a pouch that comprises a main body formed of film materials having a barrier layer and a spout of integrally molded body of olefin resin attached to a pouch main body has significantly poorer gas barrier property than a non-spouted pouch formed of film materials having the same barrier layer.

The present invention has been devised under such circumstances and aims to provide a spouted pouch suitable for achieving good gas barrier property.

Solution to Problem

A spouted pouch provided by the present invention comprises a pouch main body and a spout. The pouch main body comprises a film having a sealant layer forming an inner surface of the pouch main body. The spout is an integrally molded resin body containing both an olefin resin and ethylene-vinyl alcohol copolymer, and is attached to the pouch main body by thermal welding to the sealant layer of the pouch main body. The sealant layer comprises an olefin resin film having a heat seal strength as determined by the following peel test of 10 N/15 mm or less.

The peel test in which two olefin resin films each lined with a fracture prevention film are thermally welded in part to each other by applying a compression pressure of 0.2 MPa at 105° C. for 1 second, and subsequently the thermally welded portion of the olefin resin films is subjected to the peel test at a temperature of 23±2° C. and a tensile rate of 300 mm/min.

As described above, the spouted pouch is an integrally molded resin body containing ethylene-vinyl alcohol copolymer (EVOH) in addition to an olefin resin. EVOH is a resin material that exhibits a much lower oxygen transmission rate than olefin resins such as polyethylene. The configuration in which the spout is an integrally molded resin body containing EVOH is more suitable for realizing a spout with good gas barrier property and a pouch with good gas barrier property than configurations in which the spout is an integrally molded resin body consisting of an olefin resin. The configuration in which the spout is an integrally molded resin body containing EVOH is more easily made than configurations in which a barrier member made of EVOH is attached to the inner surface of the main body of a spout which is an integrally molded resin body of olefin resin. In addition, this configuration is suitable for realizing a spout with good gas barrier property and hence a pouch with good gas barrier property at low lost.

The sealant layer of the spouted pouch comprises an olefin resin film having a heat seal strength as determined by the above peel test of 10 N/15 mm or less. Further, as described above, the spout of the spouted pouch is an integrally molded resin body containing an olefin resin in addition to EVOH. Such a configuration is advantageous for achieving good thermal welding between the sealant layers of the spouted pouch and also for achieving good thermal welding between the sealant layers of the pouch main body and the spout. The reason is as follows.

In the case where two members are joined by thermal welding of resin materials, if the surface resin materials of the members that are involved in the thermal welding have a similarity in the behaviors of softening and melting caused upon heating for the thermal welding, the softening, melting, and mixing of the resin materials can be readily achieved by heating for the thermal welding, so that the resin materials are likely to be more securely welded after cooling. The spouted pouch of the present invention is likely to be more securely welded after cooling because the sealant layers of the pouch main body are all made of olefin resin, the softening, melting, and mixing of the resin materials can be readily achieved by heating for thermal welding. The present inventors have found that a sealant layer comprising an olefin resin film having a heat seal strength as determined by the above peel test of 10 N/15 mm or less tends to be thermally welded more securely to a spout which is an integrally molded resin body containing an olefin resin and EVOH than a sealant layer consisting of an olefin resin film that does not have such a heat seal strength. Thus, the spouted pouch has a configuration advantageous for achieving good thermal welding between the sealant layers of the pouch main body, and also for achieving good thermal welding between the sealant layers of the pouch main body and the spout.

As described above, the spouted pouch is suitable for achieving not only good thermal welding between the sealant layers of the pouch main body but also good thermal welding between the sealant layers of the pouch main body and the spout, and also is suitable for achieving good gas barrier property. Good gas barrier property of a spouted pouch is advantageous for preventing oxidative deterioration of the contents of the pouch and maintaining the quality of the contents and is therefore advantageous for guaranteeing a long sales period or shelf life for the contents of the pouch.

Preferably, the proportion of EVOH contained in the spout is 20 to 70% by mass. Such a configuration is advantageous for achieving a good balance between good gas barrier property of the spout as well as good gas barrier property of the spouted pouch and good thermal welding between the sealant layers of the pouch main body and the spout.

Preferably, the olefin resin film forming the sealant layer comprises a polyethylene resin as a main component. Such a configuration is advantageous for achieving good thermal welding between the sealant layers.

Preferably, the film for forming the pouch main body has a multilayer structure further comprising a barrier layer. Such a configuration is advantageous for achieving, for example, good gas barrier property of the spouted pouch.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of a spouted pouch according to an embodiment of the present invention.

FIG. 2 is a perspective view of the spouted pouch of FIG. 1 with its main body expanded.

DESCRIPTION OF EMBODIMENTS

FIG. 1 and FIG. 2 illustrate a pouch X as a spouted pouch according to an embodiment of the present invention. FIG. 1 is a front view of the pouch X, and FIG. 2 is a perspective view of the pouch X with its main body expanded.

The pouch X comprises a pouch main body 10 and a spout 20. The pouch main body 10 has a pair of films 11 serving as main films forming the front and back faces of the pouch main body and a pair of films 12 serving as gusset films. These films are joined together by thermal welding and form a bag called a side-gusseted pouch. In FIG. 1, seal portions 10 a and 10 b where the films 11 are thermally welded to each other are indicated by one form of diagonal hatching, and seal portions 10 c where the films 11 are thermally welded to the films 12 are indicated by another form of diagonal hatching. The films 11 and 12 may be formed of separate films or may be a folded single film.

In the pouch X of the present embodiment, each film 11 is approximately hexagonal in shape as shown in FIG. 1. As can be seen by reference to both FIG. 1 and FIG. 2, each film 12 serving as a gusset film is folded along a folding line (indicated by a dashed line seen through the film 11 in FIG. 1) and is disposed between the pair of films 11. When unfolded, each film 12 is approximately pentagonal in shape. Each film 12 is provided with a cut 12 a.

Films forming a pouch main body need to have basic properties of packaging materials, such as impact resistance, abrasion resistance, and heat resistance. In the present embodiment, the films 11 and 12 for forming the pouch main body 10 are a laminated film having a multilayer structure comprising at least a sealant layer for imparting heat sealability to the film. The films 11 and 12 are preferably laminated films having a multilayer structure comprising at least one base layer and a sealant layer. When good gas barrier property and good light shielding property are required, laminated films having a multilayer structure and further comprising a barrier layer are more preferred. In the films 11 and 12 forming the pouch main body 10, the barrier layer may be disposed outwardly of the sealant layer, for example, the barrier layer is disposed between the base layers or between the base layer and the sealant layer. The films 11 and 12 may be laminated films having a multilayer structure comprising a barrier layer and a sealant layer, the barrier layer serving also as a base layer.

The base layer described above is a layer that contributes mainly to achieving a desired strength for the pouch main body 10. Examples of the material of the film for forming the base layer include polyester resin, olefin resin, polyamide, polyacrylonitrile (PAN), polyimide (PI), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polymethyl methacrylate (PMMA), and polyethersulfone (PES). Examples of the polyester resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polycarbonate (PC). Examples of the olefin resin include polyethylene (PE) and polypropylene (PP). Examples of the polyamide include nylon 6 and nylon 66. The film for forming the base layer may be a film having a single-layer structure or a film having a multilayer structure composed of a plurality of layers of the same or different types. The film for forming the base layer may be a uniaxially or biaxially stretched film or an unstretched film.

The barrier layer described above is a layer having the function of protecting the contents of the pouch X from substances or light having properties which can affect the contents. Examples of layers having such protective function include a layer in which gas transmission rate such as oxygen transmission rate or water vapor transmission rate is low, and a layer having good light shielding property. The protective function performed by the barrier layer is chosen and adjusted depending on the contents of the pouch X. Examples of the material for forming the barrier layer include a foil of a metal such as aluminum and a resin film. Examples of the resin film include polyvinylidene chloride (PVDC), polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), and polyacrylonitrile (PAN). The barrier layer may be a layer formed by vapor deposition of aluminum, alumina, silica or the like on a predetermined base material (such as a film material for forming the base layer).

The sealant layer described above is a layer made of a resin material capable of easy thermal welding, and is disposed as an innermost layer on one side of the film 11 and 12. That region of the sealant layer of the film 11 and 12 which is not involved in thermal welding forms an inner surface of the pouch main body 10. The sealant layer comprises an olefin resin film having a heat seal strength as determined by the following peel test of 10 N/15 mm or less, preferably 7 N/15 mm or less, more preferably 5 N/15 mm or less, even more preferably 3 N/15 mm or less.

The peel test in which two olefin resin films each lined with a fracture prevention film are thermally welded in part to each other by applying a compression pressure of 0.2 MPa at 105° C. for 1 second, and subsequently the thermally welded portion of the olefin resin films is subjected to the peel test at a temperature of 23±2° C. and a tensile rate of 300 mm/min.

The above peel test can be carried out by the following method according to the method as described in the section “Heat seal strength test” in JIS Z 1707 (1997) “General rules of plastic films for food packaging”. That is, in the thermal welding process, two olefin resin films of appropriate size each of which is lined with a fracture prevention film are placed on each other and are thermally welded at their ends on one side to obtain a sample having a heat-sealed portion. The fracture prevention film is a film material having a fracture strength capable of preventing the olefin resin films to be tested from being fractured at any portion other than the heat-sealed portion in the subsequent peel test. For example, a biaxially stretched nylon film or PET film of predetermined thickness can be used as the fracture prevention film. Next, a 15-mm-wide test specimen including the heat-sealed portion is cut out from the sample obtained. The length of each film extending from the heat-sealed portion to the free end is set to a length enough to allow the initial distance between two chucks in the subsequent peel test to be 50 mm or more. In the peel test, the two films of the test specimen are opened to 180°, with the heat-sealed portion of the test specimen being in the middle between the two films, and the free end portions of the two films are attached to the two chucks of the tensile tester respectively. After that, a tensile stress is applied to the test specimen under the conditions of a temperature of 23±2° C. and a tensile rate of 300 mm/min until the heat-sealed portion is fractured, and the maximum stress during the stress application is determined. As mentioned above, the initial distance between the two chucks is 50 mm or more.

Examples of the material for forming the olefin resin film having the above heat seal strength and used for the sealant layer include polyethylene resins such as low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE), and polypropylene resins such as ethylene-propylene copolymer (EP) and polypropylene (PP). The film for forming the sealant layer may be a film having a single-layer structure or a film having a multilayer structure. The film for forming the sealant layer may be a uniaxially stretched or biaxially stretched film or an unstretched film. The olefin resin film forming the sealant layer in the pouch X or in the pouch main body 10 is preferably a film containing a polyethylene resin as a main component and particularly preferably a film containing linear low-density polyethylene as a main component. Such a configuration is advantageous for achieving good thermal welding between the sealant layers. Examples of commercially-available olefin resin films having a heat seal strength as determined by the above peel test of 10 N/15 mm or less include “UB-3” and “SE625L” (both are manufactured by TAMAPOLY CO., LTD.) and “MB-102C” and “MB-110SC” (both are manufactured by Idemitsu Unitech Co., Ltd.), all of which contain a linear low-density polyethylene film as a main component.

In addition to the above-described layers, the film 11 and/or film 12 may have another layer, for example, between the base layer and the barrier layer or between the barrier layer and the sealant layer. Further, the films 11 and 12 may have a printed layer (not illustrated) for presenting the product name of the contents, a product description such as raw materials and instructions for use, or other various designs. Such a printed layer can be formed by gravure printing, for example.

The films 11 and 12 as described above, which are laminated films, can be produced, for example, by co-extrusion lamination, dry lamination using an adhesive, or thermal lamination that bonds the layers by applying heat with a thermally adhesive layer interposed therebetween.

The spout 20 is an integrally molded resin body comprising a main body portion 21 and a cap portion 22. The main body portion 21 has a flow path (not illustrated) open to the inside of the pouch main body 10, and the cap portion 22 is an element operable to open and close the flow path. The main body portion 21 and the cap portion 22 are configured, for example, in such a manner that the main body portion 21 and the cap portion 22 are connected via a brittle connecting portion (not illustrated) when the pouch X is unopened, and the brittle connecting portion can be broken to detach the cap portion 22 from the main body portion 21 while the cap portion 22 is opened. The spout 20 is attached to the pouch main body 10 by thermal welding between the main body portion 21 and the respective sealant layers of the paired films 11 of the pouch main body 10. In FIG. 1, a seal portion 10 d where the films 11 and the spout 20 or its main body portion 21 are thermally welded is indicated by cross hatching.

The spout 20 is an integrally molded resin body containing an olefin resin and ethylene-vinyl alcohol copolymer (EVOH). Examples of the olefin resin include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ethylene-propylene copolymer (EP), and polypropylene (PP). The proportion of EVOH contained in the resin material for forming the spout 20 is preferably 20 to 70% by mass, more preferably 30 to 65% by mass, and even more preferably 35 to 60% by mass. The spout 20 of an integrally molded resin body can be produced by injection molding using a metal mold.

The pouch X having the above configuration can be produced, for example, by the following procedures. First, a set of the films 11 and films 12 for forming the pouch main body 10 are subjected to heat sealing by thermal welding in such a manner as to give the seal portions 10 b and 10 c (shown in FIG. 1). Next, in order to attach the spout 20 to the pouch main body 10, the paired films 11 and the spout 20 are subjected to heat sealing by thermal welding in such a manner as to give the seal portions 10 a and 10 d (shown in FIG. 1). Examples of the heating technique for heat sealing in the production process of the pouch X include heating with a heating jaw, impulse heating, hot air heating, and ultrasonic heating.

As described above, the pouch X is an integrally molded resin body containing ethylene-vinyl alcohol copolymer (EVOH) in addition to an olefin resin. EVOH is a resin material that exhibits a much lower oxygen transmission rate than olefin resins such as polyethylene. The configuration in which the spout 20 is an integrally molded resin body containing EVOH is suitable for achieving good gas barrier property in the pouch X. The configuration in which the spout 20 is an integrally molded resin body containing EVOH is more easily made than configurations in which a barrier member made of EVOH is attached to the inner surface of the main body of a spout consisting of an integrally molded resin body of olefin resin, and this configuration is suitable for realizing a spouted pouch with good gas barrier property at low cost.

The above-described sealant layer of the pouch X or the pouch main body 10 comprises an olefin resin film having a heat seal strength as determined by the above peel test of 10 N/15 mm or less, preferably 7 N/15 mm or less, more preferably 5 N/15 mm or less, even more preferably 3 N/15 mm or less. Additionally, as described above, the spout 20 is an integrally molded resin body containing an olefin resin in addition to EVOH. Such a configuration is advantageous for achieving good thermal welding between the sealant layers of the pouch main body 10 of the pouch X, and also for achieving good thermal welding between the sealant layers of the pouch main body 10 and the spout 20. The reason is as follows.

In the case where two members are joined by thermal welding of resin materials, if the surface resin materials of the members that are involved in the thermal welding have a similarity in the behaviors of softening and melting caused upon heating for the thermal welding, the softening, melting, and mixing of the resin materials can be readily achieved by heating for the thermal welding, so that the resin materials are likely to be more securely welded after cooling. The pouch X is likely to be more securely welded after cooling because the sealant layers of the pouch main body 10 are all made of olefin resin, and the softening, melting, and mixing of the resin materials is readily achieved by heating for thermal welding. The present inventors have found that, as described in examples described later, a sealant layer comprising an olefin resin film having a heat seal strength as determined by the above peel test of 10 N/15 mm or less tends to be thermally welded more securely to a spout which is an integrally molded resin body containing an olefin resin and EVOH than a sealant layer consisting of an olefin resin film that does not have such a heat seal strength. Thus, the pouch X has a configuration advantageous both for achieving good thermal welding between the sealant layers themselves in the pouch main body 10 and for achieving good thermal welding between the sealant layers of the pouch main body 10 and the spout 20.

As described above, the pouch X is suitable for achieving not only good thermal welding between the sealant layers of the pouch main body 10 but also good thermal welding between the sealant layers of the pouch main body 10 and the spout 20, and also is suitable for achieving good gas barrier property. The good gas barrier property of the pouch X is advantageous for preventing oxidative deterioration or the like of the contents of the pouch and maintaining the quality of the contents and is therefore advantageous for guaranteeing a long sales period or shelf life for the contents of the pouch.

In the pouch X, as described above, the proportion of EVOH contained in the spout 20 is preferably 20 to 70% by mass, more preferably 30 to 65% by mass, and even more preferably 35 to 60% by mass. Such a configuration is advantageous for achieving a good balance between good gas barrier property of the spout 20 as well as good gas barrier property of the pouch X, and good thermal welding between the sealant layers of the pouch main body 10 and the spout 20.

The spouted pouch according to the present invention is not limited to the embodiment described above. The specific configuration of the spouted pouch of the present invention can be designed or modified in various ways as long as the effect of the present invention is not impaired. Although the above embodiment describes a pouch main body with an example of the pouch main body 10 which is a side-gusseted pouch, the pouch main body is not limited to the pouch main body 10, for example. In the present invention, the pouch main body may be a flat pouch with no gusset, such as a four-side seal pouch or a three-side seal pouch, or may be a standing pouch having a gusseted bottom. Further, the spout is not limited to the spout 20 of the type which is closed with a cap, although the above embodiment describes a spout with an example of the spout 20. In the present invention, the spout may be a spout of the type which is opened by folding and removing the tip portion of the spout.

EXAMPLES Example 1 <Spouted Pouch>

A spouted pouch of Example 1 was produced, the spouted pouch having the following configuration falling within the configurations described above for the pouch X.

In the spouted pouch of Example 1, each of the films (films 11 and 12) for forming the pouch main body 10 has a multilayer structure of [PET layer (thickness: 12 μm)/AL layer (thickness: 7 μm)/NY layer (thickness: 15 μm)/LLDPE layer (thickness: 70 μm)]. In this multilayer structure, the PET layer is a base layer consisting of a polyethylene terephthalate film, the AL layer is a barrier layer consisting of an aluminum foil, the NY layer is a base layer consisting of a nylon film, and the LLDPE layer is a sealant layer consisting of a linear low-density polyethylene film (product name: “UB-3”, manufactured by TAMAPOLY CO., LTD.). For the linear low-density polyethylene film “UB-3”, the heat seal strength as determined by the peel test described above for olefin resin films for forming the sealant layers of the pouch X is 10 N/15 mm or less.

Table 1 shows the measurement result of the thermal welding temperature dependence of the heat seal strength (N/15 mm) for the linear low-density polyethylene film “UB-3” with a thickness of 50 μm (for reference, the measurement result for a linear low-density polyethylene film “SE625L” (manufactured by TAMAPOLY CO., LTD.) with a thickness of 50 μm is also shown in Table 1). Each of the values of the heat seal strength (N/15 mm) is measured by the following peel test in which two olefin resin films (objects of heat seal strength measurement) are laminated to be each lined with a biaxially stretched nylon film serving as a fracture prevention film and were thermally welded in part to each other by applying a compression pressure of 0.2 MPa at a predetermined thermal welding temperature for 1 second, and were subsequently is subjected to the peel test according to the method as described in JIS Z 1707 (1997) under the conditions of a temperature of 23±2° C. and a tensile rate of 300 mm/min.

The results summarized in Table 1 reveal that, for the same film materials (having the same composition and the same thickness), the lower the temperature during thermal welding is, the lower the heat seal strength measured in the subsequent peel test is. In addition, it is known that the heat seal strength of the thermally welded portion is likely to be lower when film materials having the same composition are thermally welded under the same thermal welding conditions, because the thicker the film material is, the smaller the rate and amount of heat transfer to the thermal welding interface are. These can lead to the conclusion that the linear low-density polyethylene film “UB-3” forming the sealant layer of each of the films for forming the pouch main body in Example 1 has a heat seal strength, as determined by the peel test described above for olefin resin films for forming the sealant layers of the pouch X, of 10 N/15 mm or less.

In the spouted pouch of Example 1, the spout 20 is an integrally molded resin body that contains 40% by mass of ethylene-vinyl alcohol copolymer (EVOH) and the rest of which is made up by high-density polyethylene (HDPE) which is an olefin resin.

As for the dimensions of the spouted pouch of Example 1, the length L1 shown in FIG. 1 is 84 mm, the length L2 shown in FIG. 1 is 133 mm, and the length L3 shown in FIG. 1 is 25 mm. In the spouted pouch of Example 1, the seal width of the seal portion 10 d (the length of the seal portion 10 d in the direction of the length L2 shown in FIG. 1) is 22 mm, and the seal width of the seal portion 10 c (for the rightmost seal portion 10 c in FIG. 1, for example, the length of the seal portion 10 c in the direction of the length L1 shown in FIG. 1) is 5 mm.

The spouted pouch of Example 1 was produced as follows: first, the pouch main body 10 was made in the form of a bag by a process in which the above set of films for forming the pouch main body 10 were subjected to heat sealing at predetermined portions, and then the spout 20 was attached to the pouch main body 10 by heat sealing using a semi-automatic spout attaching machine (manufactured by Toyo Mechanic Ltd.). In the heat sealing process, a preliminary sealing step was performed on the parts where seal portions were to be formed and was followed by a first sealing step, a second sealing step, and then a cooling step. In the preliminary sealing step, the heating temperature was 135° C., the compression pressure was 1.5 MPa, and the heating time was 2.0 seconds. In the first sealing step, the heating temperature was 115° C., the compression pressure was 1.5 MPa, and the heating time was 1.8 seconds. In the second sealing step, the heating temperature was 95° C., the compression pressure was 1.5 MPa, and the heating time was 1.8 seconds. In the cooling step, the cooling temperature was 30° C., the compression pressure was 3.0 MPa, and the cooling time was 2.0 seconds. The heating temperatures in these steps are shown in Table 2 (the same applies to Examples 2 to 7 described below).

<Seal Strength>

A partial structure corresponding to the region as indicated by a dashed-dotted line in FIG. 1 (the region including the seal portion 10 d where the sealant layers of the paired films 11 and the spout 20 are thermally welded) was cut out from the spouted pouch of Example 1, and was used as a test specimen in Example 1. For the seal portion 10 d (first seal portion) included in the test specimen, the seal strength was measured by a peel test performed under the conditions of a temperature of 23±2° C. and a tensile rate of 300 mm/min. Specifically, this measurement was performed according to the method as described in the section “Heat seal strength test for packages” in JIS Z 0238 (1999) “Testing methods for heat sealed flexible packages”.

The average of measurement values obtained for three test specimens in Example 1 was 68.4 N/15 mm. In such a manner, the seal strength was measured for the seal portion 10 d (first seal portion) of the spouted pouch of Example 1. For the predetermined four seal portions 10 c (second seal portion) where the sealant layers of the films 11 and 12 were thermally welded to each other in the spouted pouch of Example 1, the seal strength was measured in the same manner. The seal strengths of the four seal portions 10C were 72.6 N/15 mm, 73.6 N/15 mm, 81.4 N/15 mm, and 84.6 N/15 mm. These measurement results are shown in Table 2 (the same applies to Examples 2 to 7 described below).

Examples 2 to 5

Spouted pouches of Examples 2 to 5 were produced in the same manner as Example 1, except for the temperature conditions of the preliminary sealing step, first sealing step, second sealing step, and cooling step in the spouted pouch production process. The multilayer structure of the film materials forming the pouch main body 10 in Examples 2 to 5 was the same as that in Example 1. For the seal portion 10 d (first seal portion) and seal portions 10 c (second seal portion) of each of the spouted pouches of Examples 2 to 5, the seal strength was measured in the same manner as Example 1.

Example 6

A spouted pouch of Example 6 was produced, the spouted pouch having the following configuration falling within the configurations described above for the pouch X. In the spouted pouch of Example 6, each of the films (films 11 and 12) for forming the pouch main body 10 has a multilayer structure of [PET layer (thickness: 12 μm)/AL layer (thickness: 7 μm)/NY layer (thickness: 15 μm)/CPP layer (thickness: 80 μm)]. The PET layer, AL layer, and NY layer in this multilayer structure are the same as the PET layer, AL layer, and NY layer described above in Example 1, and the CPP layer is a sealant layer consisting of an unstretched polypropylene film (product code “P1146”, manufactured by TOYOBO CO., LTD.). The configuration of the spout 20, the lengths L1 to L3 described above, and the seal widths described above in the spouted pouch of Example 6 are the same as those in the spouted pouch of Example 1. The spouted pouch of Example 6 was produced by heat sealing using a semi-automatic spout attaching machine (manufactured by Toyo Mechanic Ltd.), which is the same manner as Example 1 except for the temperature conditions of the preliminary sealing step, first sealing step, second sealing step, and cooling step for heat sealing. For the seal portion 10 d (first seal portion) and seal portions 10 c (second seal portion) of the spouted pouch of Example 6, the seal strength was measured in the same manner as Example 1.

Example 7

A spouted pouch of Example 7 was produced in the same manner as Example 6 except for the temperature conditions of the preliminary sealing step, first sealing step, second sealing step, and cooling step for heat sealing in the spouted pouch production process. The multilayer structure of the film materials forming the pouch main body 10 in Example 7 was the same as that in Example 6. For the seal portion 10 d (first seal portion) and two seal portions 10 c (second seal portion) of the spouted pouch of Example 7, the seal strength was measured in the same manner as Example 1.

Comparative Example 1

A spouted pouch of Comparative Example 1 was produced as described below.

Each of the films for forming the pouch main body has a multilayer structure of [PET layer (thickness: 12 μm)/AL layer (thickness: 7 μm)/NY layer (thickness: 15 μm)/LLDPE layer (thickness: 80 μm)]. The PET layer, AL layer, and NY layer in this multilayer structure are the same as the PET layer, AL layer, and NY layer described above in Example 1, and the LLDPE layer is a sealant layer consisting of a linear low-density polyethylene film (product name: “UB-106”, manufactured by TAMAPOLY CO., LTD.). For the linear low-density polyethylene film “UB-106”, the heat seal strength as determined by the peel test described above for olefin resin films for forming the sealant layers of the pouch X is more than 10 N/15 mm. For the linear low-density polyethylene film “UB-106”, the measurement result of the thermal welding temperature dependence of the heat seal strength (N/15 mm) is shown in Table 1. The configuration of the spout 20, the lengths L1 to L3 described above, and the seal widths described above in the spouted pouch of Comparative Example 1 are the same as those in the spouted pouch of Example 1. The spouted pouch of Comparative Example 1 was produced by heat sealing using a semi-automatic spout attaching machine (manufactured by Toyo Mechanic Ltd.), which is the same manner as Example 1 except for the temperature conditions of the preliminary sealing step, first sealing step, second sealing step, and cooling step for heat sealing. The heating temperatures in these steps are shown in Table 3 (the same applies to Comparative Examples 2 to 5 described below). For the first seal portion and second seal portion in the spouted pouch of this comparative example, the seal strength was measured in the same manner as Example 1. The results are shown in Table 3 (the same applies to Comparative Examples 2 to 5 described below).

Comparative Examples 2 to 5

Spouted pouches of Comparative Examples 2 to 5 were produced in the same manner as Comparative Example 1 except for the temperature conditions of the preliminary sealing step, first sealing step, second sealing step, and cooling step for heat sealing in the spouted pouch production process. The multilayer structure of the film materials forming the pouch main body in Comparative Examples 2 to 5 was the same as that in Comparative Example 1. For the first seal portion and second seal portion of each of the spouted pouches of Comparative Examples 2 to 5, the seal strength was measured in the same manner as Example 1.

[Evaluation]

For the spouted pouches of Examples 1 to 7, a sufficiently high heat seal strength was achieved at the second seal portion, and a relatively high heat seal strength was achieved at the first seal portion. By contrast, for the spouted pouches of Comparative Examples 1 to 5, the heat seal strength at the first seal portion was relatively low and insufficient although a high heat seal strength was achieved at the second seal portion. Specifically, by each comparison between Example 1 and Comparative Example 3, between Example 3 and Comparative Example 4, and between Example 5 and Comparative Example 5 for which the temperature conditions in the heat sealing process were the same, the spouted pouch of each Example achieved a higher heat seal strength at the first seal portion than the spouted pouch of the corresponding Comparative Example. Further, by comparison between Example 6 and Comparative Example 5 for which the temperature conditions in the heat sealing process were the same, the spouted pouch of Example 6 achieved a higher heat seal strength at the first seal portion than the spouted pouch of Comparative Example 5.

TABLE 1 Unit: N/15 mm 90° C. 95° C. 100° C. 105° C. 110° C. 115° C. 120° C. 125° C. 130° C. 135° C. 140° C. 145° C. 150° C. 160° C. UB-3 — — — — — —  3.0 15.0 30.0 47.0 64.0 63.0 — — SE625L — — — —  3.0 15.0 30.0 40.0 50.0 56.0 62.0 63.0 — — UB-106 4.6 — 17.5 — 35.4 — 53.6 — 59.9 — 61.6 — 60.8 61.7

TABLE 2 1st 2nd Seal strength Seal strength Multilayer structure Preliminary sealing sealing Cooling at 1st seal at 2nd seal of film for pouch sealing step step step step portion portion main body. (° C.) (° C.) (° C.) (° C.) (N/15 mm) (N/15 mm) Example 1 LLDPE (UB-3) 70 μm 175 155 135 30 68.4 72.6 NY 15 μm 73.6 AL  7 μm 81.4 PET 12 μm 84.6 Example 2 185 165 145 30 70.0 70.5 75.4 81.3 81.4 Example 3 195 175 155 30 80.6 70.9 72.0 72.3 73.3 Example 4 205 185 165 30 81.3 64.4 66.9 67.8 73.7 Example 5 215 195 175 30 67.6 68.1 72.8 73.9 77.0 Example 6 CPP 80 μm 215 195 175 30 75.2 82.8 NY 15 μm 93.4 Example 7 AL  7 μm 225 205 185 30 71.9 85.2 PET 12 μm 93.6

TABLE 3 1st 2nd Seal strength Seal strength Multilayer structure Preliminary sealing sealing Cooling at 1st seal at 2nd seal of film for pouch sealing step step step step portion portion main body. (° C.) (° C.) (° C.) (° C.) (N/15 mm) (N/15 mm) Comparative LLDPE (UB-106) 80 μm 135 115 95 30 9.77 39.2 example 1 NY 15 μm 42.9 AL  7 μm 43.6 PET 12 μm 57.3 Comparative 155 135 115 30 47.6 69.7 example 2 71.3 77.5 80.4 Comparative 175 155 135 30 61.9 83.3 example 3 88.0 94.0 95.4 Comparative 195 175 155 30 70.5 87.3 example 4 88.9 97.2 101 Comparative 215 195 175 30 55.1 92.1 example 5 92.7 95.9 96.4

REFERENCE SIGNS LIST

-   -   X Pouch (spouted pouch)     -   10 Pouch main body     -   11, 12 Film     -   10 a, 10 b, 10 c, 10 d Seal portion     -   20 Spout     -   21 Main body portion     -   22 Cap portion 

1. A spouted pouch comprising: a pouch main body comprising a film having a sealant layer forming an inner surface of the pouch main body; and a spout being an integrally molded resin body containing both an olefin resin and ethylene-vinyl alcohol copolymer, the spout being attached to the pouch main body by thermal welding to the sealant layer, wherein the sealant layer comprises an olefin resin film having a heat seal strength as determined by the following peel test of 10 N/15 mm or less: the peel test in which two olefin resin films each lined with a fracture prevention film are thermally welded in part to each other by applying a compression pressure of 0.2 MPa at 105° C. for 1 second, and subsequently the thermally welded portion of the olefin resin films is subjected to the peel test under conditions of a temperature of 23±2° C. and a tensile rate of 300 mm/min.
 2. The spouted pouch according to claim 1, wherein a proportion of the ethylene-vinyl alcohol copolymer contained in the spout is 20 to 70% by mass.
 3. The spouted pouch according to claim 1, wherein the olefin resin film comprises a polyethylene resin as a main component.
 4. The spouted pouch according to claim 1, wherein the film has a multilayer structure further comprising a barrier layer.
 5. The spouted pouch according to claim 2, wherein the olefin resin film comprises a polyethylene resin as a main component.
 6. The spouted pouch according to claim 2, wherein the film has a multilayer structure further comprising a barrier layer.
 7. The spouted pouch according to claim 3, wherein the film has a multilayer structure further comprising a barrier layer.
 8. The spouted pouch according to claim 5, wherein the film has a multilayer structure further comprising a barrier layer. 